str1="hello world"
str2='hello world'
str3=("'hello"
      "world")
print(str1)
print(str2)
print(str3)
print('hel\'lo world')
print('123----{0}---{1}---{2}'
      'format(4,5)')

str1 = 'hello'
str2 = 'world'
print(f'123---{str1}---{str2}')
for i in range(0,101,2):
    print("======开始下载=======")
    if i == 100:
        print("下载完成")
    else:
        str4 = "*"*(i//2)+"."*((100-i)//2)
        print(f'{i}%[[{str4}]')